There are plans to update the UK military's fleet of armed vehicles
A lack of long-term planning for UK defence supplies may lead the armed forces to rely on foreign firms for equipment, industry chiefs have warned.
The Defence Industries Council told a cross-party panel of MPs there was "huge concern" procurement would not meet the needs of British troops.
The Commons Defence Select Committee also condemned the government's failure to advise on long-term requirements.
Ministers said the priority was getting equipment where it was needed most.
But the government remained focused on the long term, they insisted.
Defence Industries Council chairman Mike Turner told MPs there were concerns about Britain's ability to "play a role in the world five, 10, 15 years out".
He said: "We have a world class defence industrial base and only focusing on the short term and not the long term is of huge concern to us.
"This industry is in decline and unless people pay attention to the budgeting of defence in this country and the defence industrial base we do not have a future."
The defence committee said the Ministry of Defence needed to spell out the future requirements to British companies to avoid the armed forces having to rely on foreign supplies.
Its report said it was "crucial" the UK had the industrial capabilities to manufacture a significant proportion of equipment onshore to retain "operational sovereignty".
"Industry needs clarity about future equipment requirements to enable it to make the necessary investment," it said.
The committee raised concerns about whether the Defence Industrial Strategy would be updated at all after planned updates in December 2007 and spring 2008 were shelved.
Chairman James Arbuthnot described it as "astonishing" that Defence Minister Quentin Davies said he was "open-minded" about when a new strategy should be published.
Mr Arbuthnot, a Conservative MP, said: "We condemn the failure to publish an updated version of the Defence Industrial Strategy and consider that its continuing absence increases the risk that the UK defence industrial base will not be able to meet the future requirements of our armed forces."
One consequence was a delay in the update of the UK's fleet of armoured vehicles, he said.
"We produced a report into that procurement a couple of years ago in which we said that their attempts to procure this vehicle had been a sorry story of indecision, changing requirements and delay.
"This report says that, incredibly, it's got even worse."
The MPs said Britain's military advantage at any time depended on its investment over the previous 25 years.
"We are extremely concerned to learn that defence research spending has been cut which, in our view, is short-sighted," it said.
"We agree with the minister that it is a matter of priorities and consider that it should be a very high priority. Sufficient funding for defence research needs to be ring-fenced."
Liberal Democrat defence spokesman Nick Harvey said: "This report shows that the MoD is riddled with incompetence.
"The government must make sure our troops have the equipment they need to do their job today and in the future."
Quentin Davies, minister for defence equipment and support, insisted the government was prioritising getting new supplies to troops.
"Rightly we are prioritising getting equipment out to those who need it most, but we are also maintaining our focus on delivering long-term equipment programmes," he said.
"We have delivered equipment valued at more than £10bn to the armed forces in the last three years and continue to invest in protected mobility with £700m on 700 new armoured vehicles announced last year.
He said the government was "committed" to the Defence Industrial Strategy but that industry had made clear it did not yet want a new version.